How Marshmallow-Topped Sweet Potato Casserole Became a Thanksgiving Classic

It’s a tradition in many homes on Thanksgiving: marshmallow-topped sweet potato casserole.

As with everything related to traditions, underneath that sweet exterior there is history. Although it’s true that the modern permutation of this casserole is only a century old, the sweet potato has a much longer history. Here are three things to know about the sweet past of this favorite side dish.

Potatoes come from the Americas

Sweet potatoes were a crop that Columbus encountered when he first arrived in the Americas, writes the Library of Congress. By that time, the library writes, the root vegetables, which originate in modern Peru, “were well-established as food plants in South and Central America.”

“Columbus brought sweet potatoes back to Spain,” the library writes, “introducing them to the taste buds and gardens of Europe.” At this time, recipes that used sweet potato just called them “potatoes,” and they were popular among upper-class Brits, writes the library.

Candied sweet potatoes   

In the United States, sweet potato recipes can be found as far back as 1796, when Amelia Simmons published American Cookery.Then in the late 1800s and early 1900s, as American cookbooks boomed, everything from the incredibly well-known Boston Cooking School Cookbook (which you may know by the name of its author, Fannie Farmer) to George Washington Carver published a recipe for candied sweet potatoes. “Some call these recipes candied yams, although actual yams are a different plant altogether,” writes Miss Cellania for Mental Floss.

The oldest recipe for candied yams is from 1889, Cellania writes. Fannie Farmer’s 1918 recipe for “Glazed sweet potatoes” calls for boiling the potatoes before coating them in a sugar syrup with butter and baking “until brown, basting twice with the remaining syrup.”

Marshmallow-covered sweet potato casserole is only a thing thanks to Cracker Jacks

Sweet potatoes, because they’re a root vegetable that keep for a long time, may have been enjoyed for Thanksgiving in the 1800s. But where did the marshmallows come in? For that, according to Alex Swerdloff writing for Munchies, you have to look to a company known as Angelus Marshmallows, also the original maker of Cracker Jacks. That company, Swierdoff writes, “introduced mass-made marshmallows to Americans in 1907.”

A decade later, the corporation was still trying to get marshmallows into American homes. “They sought out Janet McKenzie Hill, the founder of the Boston Cooking School Magazine, to help them develop recipes that included marshmallows,” Swierdoff writes. The resulting cookbook, published in 1917, “featured plenty of instant classics, including fudge studded with chewy marshmallows; cups of hot cocoa dotted with them; and, yes, the first documented appearance of mashed sweet potatoes baked with a marshmallow topping,” writes Leslie Porcelli for Saveur.

Cookbook writers’ debate over this new recipe resembled a slightly more civil version of the peas-in-guacamole controversy that took the internet by storm last year. But in the end, for most people, the marshmallows won.

Kat Eschner | | READ MORE

Kat Eschner is a freelance science and culture journalist based in Toronto.